Method and apparatus for operating supplementary cells in licensed exempt spectrum

ABSTRACT

A method and apparatus for operating supplementary cells in licensed exempt (LE) spectrum. An aggregating cell operating in a frequency division duplex (FDD) licensed spectrum is aggregated with a LE supplementary cell operating in a time sharing mode for uplink (UL) and downlink (DL) operations. The LE supplementary cell may be an FDD supplementary cell dynamically configurable between an UL only mode, a DL only mode, and a shared mode, to match requested UL and DL traffic ratios. The LE supplementary cell may be a time division duplex (TDD) supplementary cell. The TDD supplementary cell may be dynamically configurable between multiple TDD configurations. A coexistence capability for coordinating operations between the LE supplementary cell with other systems operating in the same channel is provided. Coexistence gaps are provided to measure primary/secondary user usage and permit other systems operating in the LE supplementary cell channel to access the channel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/984,180, filed Jan. 16, 2014, which is the National Stage Entry under35 U.S.C. §371 of Patent Cooperation Treaty Application No.PCT/US2012/024079, filed Feb. 7, 2012, which claims the benefit of U.S.provisional application No. 61/440,288, filed Feb. 7, 2011, U.S.provisional application No. 61/560,571, filed Nov. 16, 2011 the contentsof which are hereby incorporated by reference herein.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

As the number of mobile users continues to increase, additional licensedband spectrum is needed to support these mobile users. However, licensedband spectrum is not readily available and may be very expensive toacquire. Therefore, it is highly desirable to deploy cellular radioaccess technologies (RATs) such as, for example, long term evolution(LTE), in newly available spectrum such as television white space (TVWS)or unlicensed bands, which may be collectively referred to as licensedexempt (LE) spectrum.

Operation of the deployed RATs in LE spectrum may be modified tomitigate uncoordinated spectrum usage, as well as to support uplink (UL)and downlink (DL) operation without the need for fixed frequency duplexoperation. For example, the spacing between available channels in TVWSmay depend on the current location and use of the TVWS by primary usersin the vicinity. Furthermore, some areas may only have one TVWS channelavailable, which may result in having to operate and provide both UL andDL resources on a single TVWS channel. In addition, operation over LEspectrum may be subject to the lower reliability of these channels, (ascompared to operation over the licensed bands), and to frequently stopoperation on a given channel due to high level interference, the arrivalof a primary incumbent, coexistence database decisions, and the like.

Current carrier aggregation (CA) solutions may not be appropriate forthese LE bands since the aggregated carriers may rely on the use oflicensed secondary component carriers (SCCs), which are reliable and areused by operators with confidence. However, the aggregation scenariosthey support may be rather restrictive, (for example, usuallyimplementing DL scenarios where the number of DL SCCs may exceed thenumber of UL SCCs used in the aggregation).

SUMMARY

A method and apparatus for operating supplementary cells in licensedexempt (LE) spectrum. Supplementary cells may be deployed by a system touse LE bands, for example, opportunistic, sublicensed, television whitespace (TVWS), and industrial, scientific and medical (ISM) bands. Thesupplementary cells may be aggregated with an aggregrating cellincluding, for example, primary cells and/or a secondary cells. Inparticular, the primary cell operating in a frequency division duplex(FDD) licensed spectrum may be aggregated with a LE supplementary celloperating in a time sharing mode for uplink (UL) and downlink (DL)operations. In one example, the LE supplementary cell may be an FDDsupplementary cell dynamically configurable between an UL only mode, aDL only mode, and a shared mode, to match requested UL and DL trafficratios. In another example, the LE supplementary cell may be a timedivision duplex (TDD) supplementary cell. The TDD supplementary cell maybe dynamically configurable between multiple TDD configurations. Inaddition, a coexistence capability for coordinating operations between aLE supplementary cell with other systems operating in the same channel,possibly using another radio access technology (RAT) may be provided.Coexistence gaps may be provided to measure primary and secondary userusage and permit other systems operating in the same channel as the IEsupplementary cell to access the channel.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A shows an example communications system in which one or moredescribed embodiments may be implemented;

FIG. 1B shows an example wireless transmit/receive unit (WTRU) that maybe used within the communications system shown in FIG. 1A;

FIG. 1C shows an example radio access network and an example corenetwork (CN) that may be used within the communications system shown inFIG. 1A;

FIG. 2 shows an example of television (TV) band spectrum usage;

FIG. 3 shows an example of licensed exempt carrier aggregationdeployment;

FIG. 4 shows an example of licensed exempt carrier aggregated with along term evolution (LTE) primary cell;

FIG. 5 shows an example of a high level advanced LTE spectrum solution(ALTESS) operation;

FIG. 6 shows an example of dynamic frequency division duplex (FDD)operating modes;

FIG. 7 shows example solutions for different procedures impactingsupplementary component carriers (SuppCCs) in a downlink (DL)-onlyoperating mode;

FIG. 8 shows example solutions for different procedures impactingSuppCCs in an uplink (UL)-only operating mode;

FIG. 9 shows an example of timing alignment for a 4DL:4UL relatedpattern;

FIGS. 10A and 10B show examples of hybrid automatic repeat request(HARQ) details for repeat-8 patterns, (a primary cell with an HARQround-trip-time (RTT) of 8 sub-frames);

FIGS. 11A and 11B show examples of HARQ details for a repeat-16 pattern,(a primary cell with an HARQ RTT of 16 sub-frames);

FIG. 12 shows an example of dynamically changing the direction ofaggregation through a radio resource control (RRC) reconfiguration sentover a primary carrier;

FIG. 13 shows an example of dynamically changing the direction ofaggregation through a medium access control (MAC) control element (CE)command sent over a primary carrier;

FIG. 14 shows an example of a licensed band frequency division duplex(FDD) primary cell containing both UL and DL component carriers (CCs)aggregated with a time division duplex (TDD) supplementary carrier; and

FIG. 15 shows the physical channels that are supported on each carrierof a system supporting a licensed exempt operation.

DETAILED DESCRIPTION

FIG. 1A shows an example communications system 100 in which one or moredescribed embodiments may be implemented. The communications system 100may be a multiple access system that provides content, such as voice,data, video, messaging, broadcast, and the like, to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network (CN) 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the described embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a notebook, a personal computer, a wirelesssensor, consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the CN 106, the Internet 110, and/or theother networks 112. By way of example, the base stations 114 a, 114 bmay be a base transceiver station (BTS), a Node-B, an evolved Node-B(eNB), a Home Node-B (HNB), a Home eNB (HeNB), a site controller, anaccess point (AP), a wireless router, and the like. While the basestations 114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, and the like. The base station 114 a and/or the base station 114b may be configured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple-output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a. 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link, (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, and thelike). The air interface 116 may be established using any suitable radioaccess technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as universal mobiletelecommunications system (UMTS) terrestrial radio access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as high-speed packet access(HSPA) and/or evolved HSPA (HSPA+). HSPA may include high-speed downlink(DL) packet access (HSDPA) and/or high-speed uplink (UL) packet access(HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b. 102 c may implement a radio technology such as evolved UTRA (E-UTRA),which may establish the air interface 116 using long term evolution(LTE) and/or LTE-advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,worldwide interoperability for microwave access (WiMAX)), CDMA2000,CDMA2000 IX, CDMA2000 evolution-data optimized (EV-DO), Interim Standard2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856(IS-856), global system for mobile communications (GSM), enhanced datarates for GSM evolution (EDGE), GSM/EDGE RAN (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, HNB, HeNB,or AP, for example, and may utilize any suitable RAT for facilitatingwireless connectivity in a localized area, such as a place of business,a home, a vehicle, a campus, and the like. In one embodiment, the basestation 114 b and the WTRUs 102 c, 102 d may implement a radiotechnology such as IEEE 802.11 to establish a wireless local areanetwork (WLAN). In another embodiment, the base station 114 b and theWTRUs 102 c, 102 d may implement a radio technology such as IEEE 802.15to establish a wireless personal area network (WPAN). In yet anotherembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayutilize a cellular-based RAT, (e.g., WCDMA, CDMA2000, GSM, LTE. LTE-A,and the like), to establish a picocell or femtocell. As shown in FIG.1A, the base station 114 b may have a direct connection to the Internet110. Thus, the base station 114 b may not be required to access theInternet 110 via the CN 106.

The RAN 104 may be in communication with the CN 106, which may be anytype of network configured to provide voice, data, applications, and/orvoice over Internet protocol (VoIP) services to one or more of the WTRUs102 a, 102 b, 102 c, 102 d. For example, the CN 106 may provide callcontrol, billing services, mobile location-based services, pre-paidcalling, Internet connectivity, video distribution, and the like, and/orperform high-level security functions, such as user authentication.Although not shown in FIG. 1A, it will be appreciated that the RAN 104and/or the CN 106 may be in direct or indirect communication with otherRANs that employ the same RAT as the RAN 104 or a different RAT. Forexample, in addition to being connected to the RAN 104, which may beutilizing an E-UTRA radio technology, the CN 106 may also be incommunication with another RAN (not shown) employing a GSM radiotechnology.

The CN 106 may also serve as a gateway for the WTRUs 102 a, 102 b, 102c, 102 d to access the PSTN 108, the Internet 110, and/or other networks112. The PSTN 108 may include circuit-switched telephone networks thatprovide plain old telephone service (POTS). The Internet 110 may includea global system of interconnected computer networks and devices that usecommon communication protocols, such as the transmission controlprotocol (TCP), user datagram protocol (UDP) and the Internet protocol(IP) in the TCP/IP suite. The networks 112 may include wired or wirelesscommunications networks owned and/or operated by other serviceproviders. For example, the networks 112 may include another CNconnected to one or more RANs, which may employ the same RAT as the RAN104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B shows an example WTRU 102 that may be used within thecommunications system 100 shown in FIG. 1A. As shown in FIG. 11B, theWTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element, (e.g., an antenna), 122, a speaker/microphone124, a keypad 126, a display/touchpad 128, a non-removable memory 130, aremovable memory 132, a power source 134, a global positioning system(GPS) chipset 136, and peripherals 138. It will be appreciated that theWTRU 102 may include any sub-combination of the foregoing elements whileremaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), amicroprocessor, one or more microprocessors in association with a DSPcore, a controller, a microcontroller, an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA)circuit, an integrated circuit (IC), a state machine, and the like. Theprocessor 118 may perform signal coding, data processing, power control,input/output processing, and/or any other functionality that enables theWTRU 102 to operate in a wireless environment. The processor 118 may becoupled to the transceiver 120, which may be coupled to thetransmit/receive element 122. While FIG. 1B depicts the processor 118and the transceiver 120 as separate components, the processor 118 andthe transceiver 120 may be integrated together in an electronic packageor chip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. The transmit/receiveelement 122 may be configured to transmit and/or receive any combinationof wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122, (e.g., multipleantennas), for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple radio access technologies (RATs), suchas UTRA and IEEE 802.11, for example.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),and the like), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station, (e.g., base stations 114 a, 114 b), and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. The WTRU 102 may acquire location informationby way of any suitable location-determination method while remainingconsistent with an embodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C shows an example RAN 104 and an example CN 106 that, may be usedwithin the communications system 100 shown in FIG. 1A. As noted above,the RAN 104 may employ an E-UTRA radio technology to communicate withthe WTRUs 102 a, 102 b, 102 c over the air interface 110. The RAN 104may also be in communication with the CN 106.

The RAN 104 may include eNBs 140 a, 140 b, 140 c, though it will beappreciated that the RAN 104 may include any number of eNBs whileremaining consistent with an embodiment. The eNBs 140 a, 140 b, 140 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNBs 140 a, 140 b, 140 c may implement MIMO technology. Thus, theeNB 140 a, for example, may use multiple antennas to transmit wirelesssignals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNBs 140 a, 140 b, 140 c may be associated with a particularcell (not shown) and may be configured to handle radio resourcemanagement decisions, handover decisions, scheduling of users in the ULand/or DL, and the like. As shown in FIG. 1C, the eNBs 140 a, 140 b, 140c may communicate with one another over an X2 interface.

The CN 106 shown in FIG. 1C may include a mobility management entity(MME) 142, a serving gateway 144, and a packet data network (PDN)gateway (GW) 146. While each of the foregoing elements is depicted aspart of the CN 106, it will be appreciated that any one of theseelements may be owned and/or operated by an entity other than the CNoperator.

The MME 142 may be connected to each of the eNBs 140 a, 140 b, 140 c inthe RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 142 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eNBs 140 a, 140b, 140 c in the RAN 104 via the S1 interface. The serving gateway 144may generally route and forward user data packets to/from the WTRUs 102a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eNB handovers,triggering paging when DL data is available for the WTRUs 102 a, 102 b,102 c, managing and storing contexts of the WTRUs 102 a, 102 b, 102 c,and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b, 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. For example, the CN 106 may include,or may communicate with, an IP gateway, (e.g., an IP multimediasubsystem (IMS) server), that serves as an interface between the CN 106and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102 a,102 b, 102 c with access to other networks 112, which may include otherwired or wireless networks that are owned and/or operated by otherservice providers.

FIG. 2 shows the TV band spectrum usage. Analog TV bands 200 include thevery high frequency (VHF) band and the ultra high frequency (UHF) band.The VHF band is composed of a low VHF band 205 operating from 54 MHz to88 MHz, (excluding 72 MHz to 76 MHz), and a high VHF band 210 operatingfrom 174 MHz to 216 MHz. The UHF band is composed of a low UHF band 215operating from 470 MHz to 698 MHz, and a high UHF band 220 operatingfrom 698 MHz to 806 MHz.

In the United States, the Federal Communications Commission (FCC) setJun. 12, 2009 as the deadline for replacing analog TV broadcasting withdigital TV broadcasting. The digital TV channel definitions are the sameas the analog TV channel. The digital TV bands 225 may use analog TVchannels 2 to 51 (except 37), while the analog TV channels 52 to 69 maybe used for new non-broadcast users.

The frequency allocated to a broadcasting service, but not used locally,is called white space (WS). Television WS (TVWS) refers to TV channels 2to 51, (except 37).

Besides TV signals, there are other licensed signals transmitted on theTV bands. The starting frequency of frequency modulation (FM) channel227 is 87.9 MHz, which partial overlaps TV channel 6. Channel 37 isreserved for radio astronomy 230 and wireless medical telemetry service(WMTS) 235, where the latter may operate on any vacant TV channels 7 to46. The private land mobile radio system (PLMRS) 240 uses channels 14 to20 in certain metropolitan areas. Remote control devices 245 may use anychannels above channel 4, except channel 37. The wireless microphone 250uses channels 2 to 51 with a bandwidth of 200 kHz.

Furthermore, the FCC allows unlicensed radio transmitters to operate onthe TVWS except channels 3, 4 and 37, as long as minimum interference iscaused to the licensed radio transmissions. Hence, the operation ofunlicensed radio transmitters may have to satisfy several restrictions.There are three kinds of unlicensed TV band devices (TVBDs): a fixedTVBD 255, a mode I portable (or personal) TVBD 260, and a mode IIportable (or personal) TVBD 265. Both fixed TVBDs 255 and mode IIportable TVBDs 205 may have a geo-location/database access capabilityand register to a TV band database. Access to the TV band database isused to query the allowed TV channels, so as to avoid the interferencewith digital TV signals and licensed signals transmitted on the TVbands. Spectrum sensing is considered as an add-on feature for TVBDs tominimize interference caused to digital TV signals and licensed signals.Furthermore, a sensing-only TVBD may be allowed to operate on TVWS ifits access to a TV band database is limited.

Fixed TVBD 255 may operate on channels 2 to 51, except channels 3, 4,37, but it cannot operate on the same or the first adjacent channel to achannel used by TV services. The maximum transmission power of fixedTVBD 255 is 1 W, with at most 6 dBi antenna gain. Hence, the maximumeffective isotropic radiated power (EIRP) is limited to 4 W. PortableTVBDs 260 and 265 can operate on channels 21 to 51, except channel 37,but it cannot operate on the same channel used by TV services. Themaximum transmission power of portable TVBDs 260 and 265 are 100 mW or40 mW, if it is on the first adjacent channel to a channel used by TVservices. Furthermore, if a TVBD device is a sensing-only device, thenits transmission power cannot exceed 50 mW. All the TVBDs have strictout-of-band emissions. The antenna (outdoor) height of fixed TVBD mustbe less than 30 meters, while there is no limitation on the antennaheight for portable TVBD.

A cell is typically controlled by a single base station. In LTE, aprimary cell may refer to the cell which a given WTRU camps and uses formost of its mobility related procedures. The primary cell may include,but is not limited to, an uplink component carrier (UL CC) and adownlink component carrier (DL CC) or solely to a DL CC. When a cell isaggregated with a primary cell, the aggregated cell may be referred toas a secondary cell. Although the description herein below is in termsof the primary cell, a secondary cell may also used in place of theprimary cell.

As described herein, the term supplementary cell may refer to enhancedoperations in an LE spectrum. The supplementary cell may refer to a celloperating in LE spectrum or bands in conjunction with primary andsecondary cells, (where the term aggregating cell may refer to a primarycell, a secondary cell or both). The supplementary cell may be DL only,UL only or time division duplex (TDD) UL/DL. The supplementary cell mayinclude a DL supplementary CC (DL SuppCC), an UL SuppCC or both.Although the description herein may refer to SuppCCs, it is alsoapplicable to supplementary cells.

SuppCCs may be deployed in an opportunistic fashion to make use of LEspectrum including but not limited to TVWS, industrial, scientific andmedical (ISM), sublicensed, or opportunistic bands or spectrum. In anembodiment, heterogeneous network deployments make use of advanced LEcarrier aggregation (CA) methods, systems and devices to providehot-spot overage.

FIG. 3 shows an example of LE CA deployment. A heterogeneous networkarchitecture 300 may include a core network 302, an LTE macro cell 305and an underlay of pico cells 308, femto cells 310 and remote radio head(RRH) cells 315 that may aggregate licensed and LE bands. Macro cells305 may provide service continuity, and pico cells 308 and femto cells310 may provide hot-spot coverage. A coexistence database 320 along withnew mechanisms such as coexistence gaps may be implemented to coordinateoperation with other secondary networks and users operating in LE bands.A TVWS database 325 may be used to protect incumbent users operating inthe TVWS band. Infrastructure to support dynamic spectrum trading may beimplemented across both licensed and LE bands. LE bands may be used byboth HeNB deployments or RRH/pico cell campus type deployments.

Described herein below are embodiments and examples of systems andmethods for aggregation over LE bands. In an embodiment, aggregationover LE bands may be performed by implementing a system which aggregateslicensed carriers/cells (using LTE frequency division duplex (FDD)) withone or more SuppCCs), using a time division duplex (TDD) configurationthat may be dynamically changed by the pico/femto cell, (which may bereferred to herein as enhanced TDD). In another embodiment, adynamically changed enhanced TDD configuration may be implemented toalter the duration of a guard period between uplink (UL)/downlink (DL)transitions based on the frequency of operation of a SuppCC.

An enhanced TDD operation may be implemented in another embodiment wherehybrid automatic repeat request (HARQ) feedback timing for the SuppCCmay be based on the “n+4” timing used for the primary cell. The primarycell may be used to carry HARQ feedback for the DL, and UL transmissionson the SuppCC, as well as the channel state information (CSI) for theSuppCCs. An enhanced TDD operation may be implemented in anotherembodiment where timing for UL grants for the SuppCC is based on “n+4”timing. That is, current sub-frame “n” carries UL scheduling/grant forsub-frame “n+4”. The grant information may be carried on the SuppCC orit may be carried on the primary CC (PCC), (e.g., relying oncross-carrier scheduling).

Another system embodiment may be implemented which aggregates licensedcarriers, (using LTE FDD), with one or more SuppCCs, and where theseSuppCCs may dynamically change from being configured as UL only, DLonly, or shared, (quick toggling of sub-frames from UL to DL and viceversa). A shared mode aggregation embodiment may be implemented wherethe SuppCC may rely on the primary cell CCs for sub-frame timing.

Another shared mode aggregation embodiment may be implemented whichprovides for flexible UL/DL ratios resulting in optimum DL:UL sub-framepatterns. The pattern may be based on a repeat-K structure, with N DLsub-frames followed by M UL sub-frames N+M=K. HARQ feedback may bebundled to compensate for UL/DL asymmetry. Downlink control information(DCI) may carry an indication as to the sub-frame where the informationis applicable. HARQ round-trip-time (RTT) may be variable and depend onthe sub-frame used for the prior transmission. The HARQ feedback may besent on the primary cell CC or the SuppCC based on the sub-frame usedfor the prior transmissions.

Based on the need to operate both UL and DL resources in the same LEchannel, the general approach for the embodiments described herein is touse an FDD licensed spectrum as a primary cell which provides both ULand DL primary component carriers (PCCs), and to dynamically aggregate asupplementary LE carrier in either the UL or DL for a given timeinterval. This ensures that the radio operating in the LE spectrum doesnot need to transmit or receive in the LE band simultaneously.

FIG. 4 shows an example of a supplementary LE carrier aggregated with anLTE primary cell. The LTE primary cell may include an UL CC and a DL CC,or a DL CC only. In particular, the LTE primary cell may include an FDDDL primary carrier 405 operating on a DL FDD licensed band 410 and anFDD UL primary carrier 415 operating on, an UL FDD licensed band 420,which are carrier aggregated with an UL/DL SuppCC 425 operating in a LEband 430, for example, TVWS or ISM bands. The UL/DL SuppCC may alternatebetween DL operation in one time interval 435, UL operation in anothertime interval 440. DL operation in another time interval 445 and so on.

Although the embodiments show a single SuppCC, it should be understoodthat the embodiments presented can be extended to cases with multipleSuppCCs. In all cases, the SuppCCs may be treated as additionalbandwidth to be used for communication to/from LE-capable WTRUs. Alldecisions regarding the activation, deactivation, and (re)configurationof SuppCCs may be driven by algorithms, processes and methods running ina radio resource management (RRM) functionality.

The RRM may provide an indication of the ratio of UL and DL resourcesrequired for the SuppCC(s), depending on observed system conditions. TheRRM may attempt to resolve UL congestion if this ratio is skewed to theUL side, DL congestion if this ratio is skewed to the DL side, orsystem-wide congestion, (increasing the capacity available on both theUL and DL), if the ratio is almost symmetric.

The RRM may provide some indication as to how long the supplementarycell may be used with this ratio, or additional information,(potentially providing constraints), on use of the supplementary cell.

Described herein are two embodiments that illustrate SuppCCrealizations. In the first embodiment, the FDD primary cell isaggregated with a dynamic FDD SuppCC and in the second embodiment, theFDD primary cell is aggregated with an TDD SuppCC.

Described initially are system considerations applicable to bothembodiments. A system embodiment may require a coexistence capability sothat the LTE system may coexist with other systems operating in an LEspectrum. Such coexistence may be coordinated, (via direct and/orindirect communication), or non-coordinated between the differentsystems, (the term coexistence does not presume fair usage of thespectrum). The LTE system may be able to operate even in the presence ofother systems operating in LE spectrum. The LTE system may coexist withsystems using LTE as well as other RATs. In addition, heterogeneouscoexistence with a WiFi system may be supported. In a coordinated singleRAT scenario, coexistence may allow for co-channel sharing. Innon-coordinated scenarios, coexistence may rely on lower layermechanisms, such as coexistence gaps or other interference mitigationalgorithms.

Supplementary cell operation may adapt to different types of TVWSchannels and other LE bands. For example, one type may be sublicensedchannels. A sublicensed channel may be a TVWS channel that issublicensed to an operator or user for a specific geographical area andfor a specific time which is not used by any primary user and othersecondary users, (i.e., typically a channel originally owned by adigital television (DTV) broadcast station but was made availablethrough an agreement and/or brokerage). Another example may be anavailable channel type. This type may include an available TVWS channelthat is not occupied by a primary user (PU) but may be used by anysecondary users (SU). Another example may be a PU assigned channel type.This type may be an assigned TVWS channel that is used by a PU which mayrequire SUs to leave the channel if a PU is detected.

FIG. 5 shows an example of a high level advanced LTE spectrum solution(ALTESS) in a system 500 including a WTRU 505, an HeNB 610, an HeNBmanagement system (HeMS) 515, an inter-operator coexistence manager (CM)function 520, a TVWS database 525, a coexistence discovery andinformation server (CDIS) 530, a serving gateway (SGW) 535 and amobility management entity (MME) 540.

The HeNB 510 may include a physical (PHY) layer 542, a medium accesscontrol (MAC) layer 544, a radio link control (RLC) layer 546, a packetdata convergence protocol (PDCP) layer 547, a radio resource control(RRC) layer 648, a sensing toolbox 550 and an HeNB dynamic spectrummanagement (DSM) radio resource management (RRM) entity 552. The HeNB510 may be enhanced to support operation in TVWS and other LE bands.Functions in the different LTE layers of the HeNB 510, (a PHY layer 542,a MAC layer 544, an RLC layer 546 and an RRC layer 548), may be enhancedto support the operation in the TVWS and other LE spectrum by newmechanisms and/or hooks. For example, the PHY layer 542 may be modifiedto support operation of the aggregated CCs in an LE band with no fixedfrequency duplex separation, and enhance feedback channels in LTE tosupport UL or DL only CCs, or other enhancements to support UL “heavy”configurations or optimize HARQ performance. The PHY layer 542 and theRRC layer 548 may be modified to reduce the overhead associated withcarrying unnecessary control channel information. The MAC layer 544 andthe PHY layer 542 may be modified to introduce a coexistence gap in LTEtransmissions to allow access to other secondary users. The RRC layer548 may be modified to support enhancement for measurements and todetect primary users. The RRC layer 648 may be modified to support newtriggering mechanisms to transition into the different new modes ofoperation in FDD frame structure solutions. The MAC layer 544 and theRLC layer 646 may be modified to handle DL/UL transition, especially forHARQ buffers.

A sensing toolbox 550 may be integrated in the HeNB 510 for performingand processing cognitive sensing on the LE spectrum and reporting theresults to the HeNB DSM RRM entity 552. The HeNB DSM RRM entity 652 maybe an enhancement of an existing HeNB RRM by ALTESS features related tothe TVWS spectrum management and operation. Also it maycontrol/configure the sensing toolbox operation. As described hereinbelow, RRM functions may be required to support channel allocationalgorithms that may quickly adapt to temporal variations in channelavailability and quality. The HeNB 510 may also include a coexistenceenabler function which acts as an interface between the CM 520 and thecognitive networks, for example white space radio systems or TVBDnetworks. Its functional roles are translating reconfiguration commandsreceived from the CM 520 into network-specific reconfiguration commandsand sending them to the cognitive network, so that the later canreconfigure itself.

The WTRU 505 may include a PHY layer 554, a MAC layer 556, an RLC layer558, a packet data convergence protocol (PDCP) layer 559, an RRC layer560, a sensing toolbox 562, a WTRU DSM RRM entity 564 and a non-accessstratum (NAS) layer 566. The WTRU 505 may be enhanced to support TVWSand LE operation.

Functions in the different LTE layers of the WTRU 505, (PHY layer 564,MAC layer 556, RLC layer 558 and RRC layer 560), may be enhanced tosupport the operation in the TVWS and other LE spectrum by newmechanisms and/or hooks. These may be the client side of theenhancements required as previously described for the HeNB 510.

A sensing toolbox 562 may be integrated in the WTRU 505. It isresponsible for performing and processing cognitive sensing on the TVWSand other LE spectrum and report the results to the WTRU DSM RRM entity564 and supporting measurement gaps for primary/secondary userdetection. WTRUs supporting this capability may benefit from havingaccess to a broader set of TVWS CCs. The WTRU DSM RRM entity 564 may bean enhancement of the existing WTRU RRM to support the HeNB DSM RRMentity 552 operation as well as to control and configure the operationof the sensing toolbox 562 operation.

The HeMS 515 is a third generation partnership project (3GPP) LTEoperations, administration and maintenance (OAM) entity that mayconfigure multiple HeNBs. The HeMS 515 may be able to reboot the HeNB510, setup the operating frequencies in the licensed bands, as well asPHY/MAC parameters, command the start/stop transmissions on certainfrequencies and download software to the HeNB 510.

The HeMS 515 may include a coexistence manager (CM) entity 570, anoperator's coexistence database 572 and policies 574. The CM entity 570may be responsible for managing inter-HeNBs as well as an inter-operatorcoexistence operation. For example, the CM entity 570, based oninformation received from the TVWS database 525, the CDIS 530 andsensing and usage data may process the initial list of availablechannels from the TVWS database 525 and provide channel usageinformation to the inquiring HeNB, which may include a processed list ofcandidate channels and additional information from which the HeNB mayselect the channel(s). The sensing and usage data may originate from theHeNBs under its supervision, as well as information from neighbornetworks (inter-operator), and may be stored in the operator'scoexistence database 572. The CM entity 570 may be connected to a thirdparty that provides a TVWS channel brokerage service.

The CM entity 570 may maintain the operator coexistence database 572,update the CDIS 530 and the TVWS database 525 about the networks withinthe operator's control, acquire sensing and usage data includinginformation from neighboring CM functions, and construct and maintain aninterdependency mapping for each HeNB under its supervision to identifyHeNBs and access points (APs) of the operator's network as well as othernetworks registered in the CDIS potentially interfering or impacted bythe given HeNB.

The CM entity 570 may process and forward the TVWS channel usageinformation to requesting HeNBs which may include some initial rankingof the available channels as well as proposing non-conflicting physicalcell identifiers (IDs) for each channel frequency.

The operator's coexistence database 572 may contain the TVWS usageinformation (i.e., sensing and usage data) of all networks operating inthat band which may impact the operator's own network. The operator'scoexistence database 672 may reside in the HeMS 615 next to the CMentity 570 and may contain a number of entries, each one correspondingto one HeNB entity or AP operating on TVWS bands.

An interface 576, (i.e., OAM “interface type 1”), may be used toexchange coexistence information between the HeNB 510 and the HeMS 515,as well as perform existing management functions as described below. Itmay also be used to transfer policies 574 between the HeMS 615 and theHeNB 510. The interface 576 may instruct use of a management protocol,for example a TR-069 management protocol, which supports a variety offunctionalities allowing the HeMS 515 to manage multiple HeNBs includingthe following primary capabilities: auto-configuration and dynamicservice provisioning, software/firmware image download and management,status and performance monitoring, and diagnostic. A data model for afemto cell for remote management may use the TR-069 management protocol.

The TVWS database 525 may be a geo-location database map of reservedTVWS channels for microphone and DTV signals complying to FCCregulations. Mode II or fixed TVWS devices may query directly orindirectly the TVWS database 525 by indicating their geo-location toobtain access to an available channel. In this architecture, the CMentity 570 may query the TVWS database 525 on behalf of the HeNB 510 toobtain a list of available channels.

The CDIS 530 may provide neighbor discovery service to CM entities.Based on the location provided, the CDIS 530 may respond with a list ofCMs under which networks are operating at that specific location, aswell as the contact information of those networks. TVWS usageinformation of secondary networks may be stored in the CDIS 630.However, this information may be distributed in the operator'scoexistence database 572.

The SGW 535 may be configured to perform packet routing and forwarding,lawful interception, transport level packet marking in the UL and DL,charging per WTRU, packet data network (PDN) and quality of service(QoS) class identifier (QCI), and mobility anchoring.

The MME 540 may be configured to perform NAS signaling, NAS signalingsecurity, access stratum (AS) security control, idle mode WTRUreachability, tracking area list management, PDN and SGW selection,authentication, roaming and bearer management functions.

Described herein is supplementary or supplemental cell operation. Asdescribed herein above, the supplementary cell is a cell operating in LEspectrum or bands, for example TVWS and/or ISM bands, in conjunctionwith primary and secondary cells. The supplementary cell may not operateas a standalone cell. WTRUs may not select supplementary cells in idlemode. Supplementary cells may be used to aggregate additional CCs to aprimary cell. System information block (SIB) information associated withthe supplementary cell may not be broadcast, and WTRUs operating underthis supplementary cell may be signaled associated SIB informationthrough dedicated signaling.

LE bands, such as the TVWS band, may not have a predetermined fixedfrequency duplex separation which may make it difficult to arbitrarilydefine a fixed frequency duplex separation between DL and ULtransmission. Furthermore, it may be possible that only onesupplementary CC may be available at a given time. Therefore, thesupplementary cells active in a given band may operate in TDD fashion.In one embodiment, supplementary cell aggregation using CCs may be basedon an existing TDD frame structure. In another embodiment, supplementarycell aggregation using CCs may be based on the existing FDD framestructure. In the latter case, the HeNB may dynamically change thesupplementary CCs to operate in the DL or the UL. In the case of heavyUL traffic demand, the supplementary cell will operate in UL only for along period of time until UL congestion is mitigated. For example, if ULtraffic congestion is detected, the supplementary cell currentlyoperating in DL may switch to operate in UL only operation until ULcongestion is mitigated. Furthermore, both embodiments may be simplifiedor enhanced, as supplementary cells may rely on the capability of theprimary cell to carry control and feedback information.

The supplementary cell may require the introduction of coexistence gapsto free up the medium and thus enable other wireless networks to gainaccess to the medium. During these gaps, new measurements may be takento assess usage of both primary and secondary users. Alisten-before-talk mechanism may be introduced at the end of thecoexistence gaps.

Supplementary cells may be non-Release 8 (RS) backward compatible, whichmay allow certain information overhead to be removed. Likely resourcesthat may be released are the master information block (MIB), SIB and aportion of the physical DL control channel (PDCCH) in the DL. In the UL,resources associated with the random access channel (RACH) and thephysical UL control channel (PUCCH) may also be released. A primaryshared channel (SCH) and a secondary SCH may remain for frequencysynchronization and cell search purposes.

The supplementary cells may not be as static as secondary cells as theHeNB may have to frequently stop operation on a given supplementary celldue to high level interference, the arrival of primary users orcoexistence database decisions, and the like. Active supplementary cellsmay have to operate in the presence of a higher level of interferencethan what is typically present in the licensed spectrum, and may includenew types of interferers, such as WiFi, Bluetooth® and evennon-communication interferers such as microwave ovens. Therefore,critical control information such as the PDCCH, reference symbols, andthe like, may be required to be sent in a more robust way.

Described herein is an FDD primary cell aggregating a dynamic FDDSuppCC. In particular, an FDD carrier, (operating in a licensedspectrum), aggregates a dynamic FDD supplementary carrier, (operating ina LE spectrum), using the existing FDD frame structure and which maydynamically change the SuppCC to aggregate in the DL or the UL. The CCsmay be configured to address the required ratio of UL and DL resourcesor traffic, and can be in one of three operating modes. DL only, ULonly, and shared.

FIG. 6 shows an example of dynamic FDD operating modes. A cell 600 mayinclude a primary DL CC 605 operating in a licensed hand and a primaryUL CC 610 operating in a licensed band. Also shown are threesupplementary cell CCs 615, 620 and 626 using dynamic FDD. Each of thesupplementary cells may transition between the three operating modes. Inone example, the supplementary cells may transition independently fromeach other. For example, supplementary cell1 615 may transition from aDL only mode 630, to an UL only mode 632, back to another DL only mode634 and then to a shared mode 636. In this embodiment, supplementarycell may be activated and deactivated as needed. For example,supplementary cell2 620 is deactivated between times T1 and T3 640.

The SuppCCs may not necessarily be the same size as the licensed bandcarriers. For example, the three SuppCCs 615, 620 and 625 may be 5 MHzSuppCCs in aggregation with a 10 MHz primary FDD cell, (which mayinclude both an UL and DL CC). If more than one SuppCC is configured,the operating mode may be the same across all activated SuppCCs. Thismay be performed to reduce the implementation complexity at the WTRUs.In the embodiment shown, all SuppCCs are operating in DL only modebetween times T3 and T4.

In one example, the SuppCCs may be in a DL-only mode, characterized by adesired DL:UL ratio heavily skewed on the DL. This mode may be used torelieve DL congestion. The cell may schedule DL transmissions on theseDL SuppCCs to all capable WTRUs.

In another example, the SuppCCs may be in an UL-only mode, characterizedby a desired DL:UL ratio heavily skewed on the UL. This mode may be usedto relieve UL congestion. The cell may schedule UL transmissions onthese UL SuppCCs to all capable WTRUs.

In another example, the SuppCCs may be in a shared mode, characterizedby carriers which may quickly toggle between the UL and the DL. Forexample, the toggling interval may be of an order of several sub-frames.In particular, over a period K+L sub-frames, the SuppCCs may be used forDL transmissions in K sub-frames and for UL transmissions in Lsub-frames. K and L, are chosen to match the requested DL:UL ratio(DL:UL˜K/(K+L):L(K+L)). For example, supplementary cell3 625 shows a50%:50% DL/UL ratio, with the supplementary cell CC toggling everyseveral sub-frames 645.

In addition, although FIG. 6 shows only a primary serving cell and anumber of supplementary cells, it should be understood that theaggregation may extend over a number of secondary serving cells.

If required, an LTE system may operate a SuppCC on a single operatingmode, (deactivating the SuppCC when no longer needed). Alternatively,the LTE system may dynamically change from one operating mode toanother.

The DL-only operating mode may be characterized by the primary CCs (ULand DL) aggregated with one or more DL SuppCCs. The cell may uses theSuppCCs as additional bandwidth on which it may schedule DLtransmissions. FIG. 7 shows example solutions for different proceduresimpacting SuppCCs in a DL-only operating mode.

The UL-only operating mode may be characterized by the primary CCs (ULand DL) aggregated with one or more UL SuppCCs. The cell uses theSuppCCs as additional bandwidth on which it may grant UL capacity to aWTRU. FIG. 8 shows example solutions for different procedures impactingSuppCCs in an UL-only operating mode.

In a shared operating mode, the pico/femto cell may determine the bestpattern to match the requested DL:UL ratio requested from the RRMfunctionality. The pico/femto cell may determine this dynamically,(e.g., based on some formulas, or it may have a preconfigured set). Whendetermining the optimum pattern, the pico/femto cell may rely on anumber of guiding principles including, for example, minimizing thenumber of UL to DL transitions and DL to UL transitions, or minimizingthe effect on hybrid automatic repeat request (HARQ) procedures thatdeal with positive acknowledgement (ACK)/negative acknowledgement (NACK)transmission and HARQ retransmissions.

The SuppCC using a shared operating mode may rely only on sub-frametiming, which may be derived from the PCC. The DL sub-frames may be timealigned with the DL sub frames on the DL PCC.

FIG. 9 shows an example of timing alignment for a 4DL:4UL relatedpattern. A cell 900 may include a DL PCC 906 and an UL PCC 910. The cell900 may be aggregated with a SuppCC 915. In this embodiment, while theUL sub-frames 920 are time aligned with the UL PCC sub-frames 925, theUL sub-frames 920 may be time-advanced to reduce the potentialinterference with the DL sub-frame transmissions 930. This timingadvancement may be tied to that of the PCC.

At the DL-UL transition 935, the DL sub-frame 940 may be a specialsub-frame that is only partially used for data transmission. The rest ofthe sub-frame 940 may be a guard (gap) period 945 which may be used toallow the WTRU to transition from reception to transmission mode.Although the system may be flexible to support any DL:UL pattern, thepattern may repeat every K sub-frames, (hereafter referred to as arepeat K pattern), where K is a multiple of the number of HARQ processesused in the primary cell, (8 for an FDD LTE system). In such a case, theWTRU and the pico/femto cell may use modified HARQ and retransmissionrules to send ACK/NACK feedback, as well as retransmissions, (e.g., as aresult of a NACK reception).

For a repeat-8 pattern, the retransmissions may occur exactly a number(n+8) of sub-frames after the previous transmission. The HARQ feedbackmay be carried either on the primary cell, or it may be carried in theSuppCC. For the latter case, (use of SuppCC), the feedback may bebundled to deal with the UL/DL asymmetry.

FIGS. 10A and 10B show examples of HARQ details for repeat-8 patterns,(a primary cell with an HARQ round-trip-time (RTT) of 8 sub-frames).FIG. 10A shows an example for DL:DL pattern of 4:4 and FIG. 10B shows anexample for DL:DL pattern of 2:6. Although FIGS. 10A and 10B arediscussed with respect to a primary cell, it is applicable tosupplementary cells. In general, for the 4:4 pattern 1000, each DLsubframe 1002, 1004, 1006, and 1008 may carry feedback for an ULsubframe 1003, 1006, 1007 and 1009, respectively. This is alsoapplicable for UL subframes carrying feedback information for DLsubframes. Although FIGS. 10A and 10B are discussed with respect to aprimary cell, it is applicable to supplementary cells as appropriate.

For the 2:6 pattern 1020, the feedback for the DL transmissions do notneed to be bundled. However, the 2 DL sub-frames 1025 and 1030, (in eachset of 8 sub-frames), need to carry feedback for 3 UL subframes 1035 and1040, respectively. The UL HARQ feedback may be carried in a feedbackchannel, (e.g., a modified physical HARQ indicator channel (PHICH) forLTE), or in a new feedback channel visible to only WTRUs capable ofcarrier aggregation over LE bands. In the 2:6 pattern 1020, UL subframes1045 and 1050 may carry feedback for DL subframes 1055 and 1060,respectively.

For the repeat-8 patterns, the DL control signaling, (DL scheduling andUL grants), may be carried on the primary cell relying on the timingrules for the primary cell and cross carrier scheduling. As shown inFIG. 10A for the 4:4 pattern, the DL scheduling information for frame“n” may be carried in frame “n”. UL grants carried in frame n may beused to schedule future transmissions in frame “n+k”, where k depends onthe repeat-8 pattern. The value of k may be signaled with the grant, orderived implicitly, (e.g., based on a specific WTRU address for examplea radio network temporary identity (RNTI), where k refers to grant forUL sub-frame k).

Alternatively, the DL control information may be carried on the DLsub-frames using a form of bundled grant. In this case, the DLsub-frames may have to provide UL grants for more than one UL sub-frame.As shown in FIG. 10B for the 2DL:6UL pattern, a DL sub-frame, forexample subframe D1, may provide UL grants for 3 UL sub-frames, forexample sub-frames U1, U3 and U5. This asymmetric pattern may requireadditional processing. For example, in 3rd Generation PartnershipProject (3GPP) Release 10, the UL grant may contain an identity of theWTRU to whom the grant applies. For asymmetric shared mode operation,the UL grant may also have to contain an indication of the time at whichthis grant applies, (the grant received in frame n applies to ULsub-frame n+k). The value of k may be explicitly included in the grantinformation, (e.g. grant applies to WTRU 1 in sub-frame n+6).Alternatively, the value of k may be determined implicitly. Forinstance, a WTRU could be assigned 3 addresses, (radio network temporaryidentifier (RNTI_2), RNTI_4, and RNTI_6). Receiving an UL grant forRNTI_6 implies that the grant applies to this WTRU in frame n+6.

FIGS. 11A and 11B show examples of HARQ details for a repeat-16 pattern,(a primary cell with an HARQ RTT of 16 sub-frames). For a repeat-16pattern, the retransmission schedule may be based on the sub-frame usedfor the initial transmission. FIG. 11A shows an example of a DL:UL 4:12pattern 1100, where the HARQ feedback is carried on the SuppCC usingbundled HARQs 1105, 110, 1115 and 1120, for example. The HARQ RTT is 16sub-frames and would require an increase in the maximum number of HARQprocesses. For example, the number of HARQ processes in the UL may be12.

FIG. 11B illustrates an alternative feedback mechanism for DL:UL 4:12pattern 1125, where all or part of the HARQ feedback may be carried inthe primary cell. The feedback for UL sub-frames U1, U2, U3, and U4 arecarried on the primary cell 1130. For example, the acknowledgement(ACK)/negative ACK (NACK) for the packet sent in the UL at subframe U1is sent by the base station over the primary cell on the DL CC using thePIHCH 4 subframes after transmission of the packet. The feedback for ULsub-frames U5-U12 may be carried in the SuppCC 1140. For feedbackcarried on the primary cell, the FDD LTE “n+4” timing rules may be used.If the primary cell is used to carry feedback, it is possible tomaintain the number of HARQ processes to 8. For this alternativeapproach, the WTRU and pico/femto cell may be aware of the HARQ RTT foreach of the sub-frame, as well as where the feedback is beingtransmitted. For DL sub-frames 1-4, the RTT is 16 sub-frames. For ULsub-frames 1-4, the RTT is 8 sub-frames. For UL sub-frames 5-12, the RTTis 12 sub-frames.

Described herein are embodiments for dynamic control of the SuppCC. Inone embodiment, the direction of the aggregation may be dynamicallychanged through an RRC reconfiguration sent over the primary carrier.FIG. 12 shows a cell 1200 that may include an FDD DL primary carrier1205 operating in a DL FDD licensed band and an FDD UL primary carrier1210 operating in an UL FDD licensed band. The cell 1200 is aggregatedwith a SuppCC 1215 operating in a LE band such as a TVWS or ISM band.Initially, the aggregation direction is in the UL direction 1220. A RRCReconfiguration message 1225 is received. In general, LTE delivers andprocesses RRC messages within 15 ms in connected mode. The aggregationdirection is then changed to the DL direction 1230.

In another embodiment, the direction of the aggregation may also bedynamically changed through a medium access control (MAC) controlelement (CE) command sent over the primary carrier. FIG. 13 shows a cell1300 that may include an FDD DL primary carrier 1305 operating in a DLFDD licensed band and an FDD UL primary carrier 1310 operating in an ULFDD licensed band. The cell 1300 is aggregated with a SuppCC 1316operating in a LE band such as a TVWS or ISM band. RRC reconfigurationmessages 1320 may have preconfigured both UL and DL SuppCCs in the LEspectrum. Initially, the SuppCC 1315 may have aggregation activated inone direction 1322. A MAC CE message 1325 may subsequently activate aSuppCC 1315 aggregation in another direction 1330 and deactivate theSuppCC aggregation in the other direction 1322.

A new MAC scheduler and buffering scheme may be used to retaintemporarily deactivated UL or DL MAC protocol data units (MPDUs) whenswitching the SuppCC from DL to UL, or vice versa. Note that both FDDcarriers make aggregation synchronous and additional memory may not berequired.

In addition, new guard periods (GPs) may be added for dynamic FDD priorto any transition of the SuppCC from DL to UL, or vice versa. This mayapply also for any transitions from one operating mode to another,(e.g., from the DL-only operating mode to the UL-only operating mode).This guard period may be configured based on the range or size of thecell. It may also be changed/reconfigured dynamically via RRCreconfiguration messages.

PHICH may be transmitted on the DL carrier that was used to transmit theUL grant. The timing of responses to be expected on the PHICH may differin FDD and TDD. For FDD, DL ACK/NACK may be sent 4 subframes after theUL transmission, but in TDD this may be variable. The mapping of PHICHresources may also differ. In FDD, all frames may have the same numberof PHICH resource elements in the first orthogonal frequency divisionmultiplexing (OFDM) symbol. In TDD, the number of PHICH resourceelements may depend on the subframe. In TDD, the size of the PHICH maybe adjusted based on the UL/DL configuration, (an UL-heavy configurationmay have more resource elements allocated to the PHICH). PHICHcollisions may be considered for the case of cross-carrier scheduling,(resolved by a demodulation reference signal (DMRS) cyclic shiftmechanism).

Therefore, if an FDD carrier is used in white space, this could resultin an UL heavy configuration with a potential for PHICH collisions. Onepossibility is to define an additional PHICH allocation which may besent over the RRC reconfiguration message while configuring the SuppCC.These PHICH configurations may be changed when the SuppCC isreconfigured from UL to DL in order to adapt to the load, (either ULheavy or DL heavy), of the channel. The PDCCH in the licensed band,(allocation and configuration), may then be modified based on the newPHICH allocations that occur in the first OFDM symbol of each subframe.

When the unlicensed band carrier is set to DL only, the unlicensed bandUL control information like channel quality indication (CQI)/precodingmatrix information (PMI)/rank indication (RI), ACK/NACK/discontinuoustransmission (DTX) may be sent over the primary carrier FDD UL. Theformat of the control information will include corresponding bit fieldson FDD UL for that purpose.

Described herein is an FDD primary cell aggregating an TDD SuppCC Inparticular, a primary FDD carrier operating in a licensed bandaggregates with a SuppCC operating in a LE band based on an existingLTE-TDD frame. Multiple UL and DL supplementary transmissionopportunities may exist in each frame, depending on asymmetryconfiguration.

FIG. 14 shows an example of a licensed band FDD primary cell 1400containing an UL CC 1406 and a DL CC 1410 aggregated with an TDDsupplementary cell 1415, (may also be referred to as enhanced TDDsupplementary cell and the term “enhanced TDD supplementary carrier” maybe used in appropriate situations or as needed). The TDD supplementarycell 1415 may be treated by the system as additional bandwidth resourcesfor both UL and DL. This additional resource may be usedopportunistically by the base station if the RRM determines the need forit and an available channel may be found. When an TDD supplementary cell1415 is activated by the RRM, the base station may have access to anadditional TDD-like component cell with which aggregation may beperformed. Effectively, DL carrier aggregation may occur over subframesin which the TDD supplementary cell is in the DL direction, and ULcarrier aggregation may occur over subframes in which the TDDsupplementary cell is in the UL direction. During a gap 1420, the TDDsupplementary cell 1415 does not provide additional bandwidth foraggregation. Aggregation may be performed by combining one or more TDDsupplementary cells with a licensed band PCC and zero or more SCCs.

The TDD supplementary cell 1415 and the FDD licensed carriers 1405 and1410 may inherently have different timing relationships for variousoperations, most of them related to HARQ. In the case where the TDDsupplementary cell 1415 and licensed carriers 1405 and 1410 operateindependently, these timing relations may not have any impacts on thePHY and MAC layers of the system. However, to allow cross-carrierscheduling of resources on the TDD supplementary cell 1415 from thelicensed band carriers 1405 and 1410, procedures do not currently exist,within the 3GPP standards to define the behavior of grants,retransmissions, and timing of power control commands.

In order to resolve the discrepancy in timing, an enhanced TDDsupplementary cell 1415 may be used in which the procedures for HARQtiming and PHY control channels, (PDCCH. PUCCH, and PHICH), aredescribed herein below. These procedures differ from those defined inthe 3GPP standards for a standard TDD CC, and the differences may allowthe enhanced TDD CC to function in the most efficient way with an FDDlicensed LTE system.

For the enhanced TDD frame structure, a dynamic UL/DL configuration anddynamic frequency dependant guard period (GP), (shown as gap 1420), maybe implemented. The TDD frame structure, (referred to as a framestructure type 2), defined in the 3GPP standards, provide 7 differentfixed UL/DL configurations that may be used in a static fashion. Onceconfigured, these configurations may be used for all WTRUs throughoutthe cell and may not change. In HeNB deployments, the number of WTRUsserved by the HeNB may be quite smaller than a macro-cell deployment.Therefore, the traffic load, (UL, DL, or balanced), may change morefrequently and in a more pronounced fashion. Since the TDD UL/DLconfiguration in 3GPP may be fixed, introducing a regular TDD componentcarrier in the LE bands results in some limitations in the efficiency ofthe bandwidth use relative to the traffic load.

One approach to mitigate the TDD limitation may be to dynamically changethe configuration of UL/DL in TDD by sending to the active WTRU, througha RRC reconfiguration message or system information, the newconfiguration information. As a result, in the enhanced TDDsupplementary cell, the RRM may control the UL/DL configuration of theenhanced TDD supplementary cell based on the traffic load at any giventime. At any given time, one of the 7 UL/DL configurations may be usedfor the enhanced TDD supplementary cell in order to best suit thetraffic load at the HeNB. For example, for a DL heavy traffic load,(several WTRUs performing heavy download of video, for example), theHeNB may configure UL/DL configuration 5 for the enhanced TDDsupplementary cell. This may allow the UL/DL configuration to adjust tothe traffic load over the cell.

The system information about the enhanced TDD supplementary cell UL/DLconfiguration would be sent by the PCC on the licensed band. Followingthe sending of the signaling representing the change in the UL/DLconfiguration, the base station may change the UL/DL configuration, (andtherefore the sequence of transmit and receive subframes on the enhancedTDD supplementary cell), after a certain number of subframes. Potentialcandidates for the switching time may be the frame boundary or thearrival of the first special subframe on the enhanced TDD supplementarycell. These switch points may avoid the switching from DL to UL that mayoccur when a configuration is changed dynamically. Other switch pointsthat avoid a DL to UL transition may also be possible, and the signalingwhich indicates the change of the UL/DL configuration may potentiallydefine the switch time as part of the messaging.

Idle mode WTRUs may not be impacted by a change in UL/DL configuration,as camping on the primary carrier or multiple UL/DL configurations maybe preconfigured through an RRC message and activated by a MAC controlelement (CE) message. In addition, since carrier aggregation is not usedin idle mode, the change of the UL/DL configuration on these WTRUs maybe transparent until RRC connection, (at which time they receive thecurrent UL/DL configuration to be used). The UL/DL configuration of allconfigured TDD supplementary cells may be signaled at the time of RRCconnection. Any changes to the UL/DL configuration may be signaledthrough an RRC reconfiguration or through a dedicated SIB, (since theUL/DL configuration may be applied to the entire system utilizing the LEbands).

As illustrated in FIG. 14, TDD may require a gap (GP) 1420 in thespecial sub frame 1422, (where a Downlink Pilot Timeslot (DwPTS) 1424and an UL Pilot Timeslot (UpPTS) 1426 are included for configuration andprocessing purposes), to avoid interference during switching between ULand DL. In the enhanced TDD supplementary cell, the GP duration may beconfigurable through RRC reconfiguration or system information change toallow for the configuration to dynamically adjust to the range of theTDD supplementary cell as well as the frequency band of the unlicensedspectrum being used, (the propagation characteristics of the signal maychange as the frequency is changed). A preconfigured GP value perfrequency band is also possible. This preconfigured GP may be based onthe expected cell size and propagation characteristics over the LEchannel in question, and be modified by an RRC message when thefrequency band of the supplementary carrier is changed.

For the HARQ entity on the enhanced TDD supplementary cell, the FDD HARQtiming may be used to define the operations of grants, acknowledgements,and retransmissions on the supplementary carrier. In order to allow theuse of FDD-like timing for these operations on the supplementarycarrier, the presence of the PHY-layer control channels present on thelicensed carriers (PCC and SCC) may be leveraged. Unlike a pure TDDsystem, the PHY-layer control channels on the licensed FDD carriers maybe present on every subframe and may therefore be leveraged to allow FDDtiming for operations involving the enhanced TDD supplementary cell. Inorder to allow this, the use of the PHY control channels on the enhancedTDD supplementary carrier may be restricted so that the enhanced TDDsupplementary cell may not carry a PHICH channel, and allacknowledgements to UL transmissions made by the WTRU may be sent onlyon the PCC or SCC. The enhanced TDD supplementary cell may not carry aPUCCH channel. The PUCCH may be transmitted on the PCC only. The PDCCHmay or may not be transmitted on the TDD supplementary cell. FIG. 15shows the physical channels that are supported on each carrier of asystem supporting a licensed exempt operation.

UL grants addressed to the enhanced supplementary carrier may be sentfour subframes prior to when the grant takes effect. These grants may besent using the PDCCH on either the PCC/SCC, (assuming cross-carrierscheduling), or on the supplementary carrier itself. When cross-carrierscheduling is used, downlink control information (DCI) format 0 is usedto send the grant and may contain a carrier indication field (CIF) toindicate the enhanced supplementary carrier that carries the grant. Thescheduler may ensure that an UL grant is never sent four subframes priorto a DL subframe on the enhanced TDD supplementary cell. These rulesapply for both PDCCH sent on the PCC/SCC and PDCCH sent on thesupplementary carrier.

As in regular TDD. DL allocations for resources on the enhanced TDDsupplementary cell may be sent on the same subframe where the allocationtakes place, and may therefore be sent on a subframe where thesupplementary carrier is a DL or special subframe.

The presence of control channels on every subframe, (due to leveragingthe licensed band), may allow a system aggregating an enhanced TDDsupplementary cell to send ACK/NACK n+4 subframes following the actualdata transmissions in both UL and DL. Although ACK/NACK may be sent fordata transmissions from the enhanced TDD supplementary carrier after 4subframes of the transmission, other values for a fixed data to ACKdelay may also be possible.

For DL transmission on the supplementary carrier, ACK/NACK may be senton either the PUCCH on the PCC or the physical UL shared channel(PUSCH), (if a PUSCH is allocated in the given subframe). Due to theavailability of UL subframes on the PCC, the WTRU may send ACK/NACKaccording to FDD timing. As with LTE Release 10, PUSCH may be leveragedfor sending ACK/NACK if a PUSCH is present in the subframe where thefeedback must be sent. The supplementary carrier PUSCH may also be usedto send ACK/NACK if PUSCH is not allocated to the particular WTRU on PCCor SCC but is allocated on the enhanced supplementary carrier for thatsubframe.

For UL transmission on the supplementary carrier, ACK/NACK may be senton the PHICH of the PCC or SCC. Due to the presence of DL subframes onthe PCC/SCC, the base station may send ACK/NACK using the FDD) timing.The PHICH may not be present on the supplementary carrier due to thepresence of UL subframes that do not carry the PHICH and may limit theability to transmit ACK/NACK using the FDD timing.

Since retransmissions on the supplementary carrier depend on thepresence of a DL or UL subframe on those retransmissions, the n+4 FDDtiming may not be applied in the case of retransmissions.

Physical random access channel (PRACH) procedures and structure in TDDmay be quite different from FDD. The PRACH procedures in LTE may consistof 6 resource blocks (RBs) adjacent to the PUCCH in predeterminedsubframes. For a given PRACH configuration (from SIB2), mapping tospecific subframes is different in TDD versus FDD. In FDD, there may beat most one PRACH available per subframe. In TDD, there may be multiplePRACH resources in a given subframe, (to account for fewer UL subframesin a frame). The offset between RACH resources in a subframe may begiven by upper layers. Preamble format 4 may be used only in TDD, (shortpreamble used to fit into an UL pilot timeslot (UpPTS) of the specialsubframe).

For a system aggregating with an enhanced TDD supplementary cell, thePRACH may be implemented in the primary cell which may be FDD.Therefore, the configuration, timing, and procedure for PRACH may followthe FDD case. However, the network may trigger an additional PRACHprocedure that is initiated on the supplementary carrier in the eventthat timing alignment between primary and supplementary carriers may besignificantly different due to large frequency separation. In this case,RRC reconfiguration associated to adding the supplementary carrier mayneed to define the specific RACH configuration to be used on thesupplementary carrier which may include an TDD RACH procedure. The RRCconfiguration that is sent over the FDD carrier may specificallyindicate that the RACH configuration is specific to the TDD carrier.This particular type of RACH may be triggered when the WTRU has data tosend to the base station, or when the base station has detected a timingdrift, between the primary and supplementary carriers.

When performing PRACH on the TDD supplementary carrier, contentionresolution may take place on either the primary or supplementarycarriers in order to ensure a larger number of available PRACH resourcesfor the system.

Timing of UL power control for a PUSCH relative to a transmit powercontrol (TPC) command is different in TDD and FDD. A new entity may beadded in the base station that is aware of the timing difference betweenthe power control changes on the TDD and FDD carriers and applies theappropriate transmit power control (TPC) command. If cross carrierscheduling is supported. TPC commands for FDD or TDD may bedifferentiated by adding a field to the PDCCH for a TPC command or usinga carrier specific schedule for TPC.

TDD may support bundling of multiple ACK/NACKs into a single ACK/NACK tobe sent in the UL subframe. FDD may not support this mode, (single ACKis sent for each received transport block). ACK/NACK bundling may becontrolled by the downlink assignment index (DAI) sent in the DCI on thePDCCH (2 bits). These two bits may not be present in FDD mode DCIformats. When multiple serving cells are configured, ACK/NACK bundlingmay not be performed, (but multiplexing may still be possible). ACK/NACKrepetition, (configured by upper layers), in TDD mode may be applied forACK/NACK bundling and not for ACK/NACK multiplexing.

Cross-carrier scheduling of DL resources on the TDD supplementarycarrier may be allowed via the FDD carrier. For cross carrierscheduling, the FDD carrier may need to include the DAI in the DCIformat. Additional complexity in blind decoding of PDCCH may berequired. Because ACK/NACK may be sent on PUCCH, bundling may need to besupported on the FDD UL carrier, (the base station may need to be ableto decode the PUCCH related to the bundled information). As a result,the bundling operation may be performed relative to the transport blocksreceived in the TDD supplementary carrier, but the bundled ACK/NACKs maybe sent over the FDD carriers. In addition, sending the bundled ACK/NACKover the TDD supplementary carrier may be supported as well, usingPUSCH. This is due to the fact that, in a combined TDD/FDD design,ACK/NACK may not be sent only on the primary carrier. Instead, ACK/NACKmay be sent on a secondary carrier if there is a PUSCH allocated on it,but no PUSCH on the primary carrier.

Periodicity and timing of the sounding reference signal (SRS) may becontrolled by upper layer parameters and may be different between TDDand FDD. An SRS may be transmitted in UpPTS in TDD, (UpPTS may bereserved for SRS and format 4 PRACH). Different sub-frame configurationsmay be sent for each carrier when both TDD and FDD are configured,(i.e., an TDD supplementary carrier or cell, as appropriate). Thisadditional SRS configuration may be sent over the primary carrier.Fields may therefore be added to the SRS configuration to identifywhether the configuration corresponds to TDD or FDD.

In contrast to FDD, in TDD, special frames may not have PUCCH mapped tothem. The PUCCH may be transmitted on the primary cell in an FDDfashion.

For CA, a PHICH may be transmitted on the DL carrier that was used totransmit the UL grant. The timing of responses to be expected on thePHICH may differ in FDD and TDD. For FDD, a DL ACK/NACK may be sent 4subframes after the UL transmission, and in TDD this may be variable.The mapping of PHICH resources may also differ. In FDD, all frames mayhave the same number of PHICH resource elements in the first OFDMsymbol. In TDD, the number of PHICHs may depend on the subframe. In TDD,the size of the PHICH may be adjusted based on the UL/DL configuration,(UL-heavy configuration may have more resource elements allocated toPHICH). PHICH collisions may be considered for the case of cross-carrierscheduling, (resolved by demodulation reference signal (DMRS) cyclicshift mechanism).

A PHICH may be sent on the licensed band, (in order to ensure n+4 timingfor ACK/NACK on the enhanced TDD supplementary carrier). New proceduresmay be required in order to define the PHICH resources on the licensedband when scheduling of the supplementary carrier is performed by thePDCCH on the supplementary carrier. A default licensed carrier (the PCC)may be chosen for sending the PHICH in this case, and the scheduler mayavoid PHICH collisions through smart scheduling. Alternatively, thePHICH may be sent on the supplementary TDD carrier, (to make use of theadjustable PHICH resources available on this carrier), if the n+4 HARQtiming is not assumed.

Some DCI Formats on PDCCH may be different between TDD and FDD, (e.g.,DCI format 1 for FDD may be 3 bits for a HARQ process and 2 bits forDAI, while 4 bits for an HARQ process and no bits for DAI, for TDD). Ifcross carrier scheduling is being used on the primary carrier, a newPDCCH search space may be allocated in order to decode both TDD and FDDDCI formats which may be separate from the FDD PDCCH search space. Thismay simplify blind decoding of the PDCCH.

Uplink grants may be signaled by the PDCCH using DCI format 0. In FDD,an UL grant may start 4 subframes after DCI format 0 is received, (DCIformat 0 may also be different for TDD/FDD). In TDD, the UL index in DCIformat 0 may specify the timing of the grant. In order to docross-carrier scheduling in the UL with a LE supplementary TDD carrier,a new TDD DCI format 0 may be used to be better aligned with the FDD DCIformat. The information from the DCI sent on the FDD carrier may specifyboth whether the UL grant is specific to the FDD or TDD carrier, andwhen it may be scheduled when it is specific to the TDD carrier.

To support DL heavy CA configurations, PUCCH format 3 may be used toallow a larger number of bits for ACK/NACK, (when format 1b with channelselection does not have sufficient bits for the required ACK). In FDD,10 bits may be allocated in PUCCH format 3. In TDD, 20 bite may beallocated in PUCCH format 3. The ACK/NACK may be treated forsupplementary TDD carrier as an FDD supplementary carrier. There may notbe a need to implement ACK/NACK bundling, as it is the case for TDD, asthere is always an UL FDD carrier active (primary carrier) in thisapproach.

If an TDD carrier is used, the way in which system information may beinterpreted for CQI reporting may have to be different for the TDD orFDD carrier, (alternatively, separate system information (SI) for FDDand TDD may be needed). Mixing TDD and FDD may be more complex for thescheduler as well, which may need to be able to handle two differentschedules of TDD and FDD to come up with the DL allocation decisions.Upper layer event reporting and measurements may also need to bemodified given different timing for CQI reports coming from the TDD andFDD carrier.

Described herein are coexistence embodiments. Spectrum sharing amongsecondary users may require an effective use of the LE bands. If it isnot coordinated well, the bands may be either left unoccupied, resultingin a waste of frequency bands, or heavily accessed by secondary users,causing significant interference with each other. Therefore, a welldesigned coexistence mechanism is desirable to enable an effective usageof the LE bands and improve the communication quality of the secondarynetworks.

Referring back to FIG. 1, a database enabled coexistence solution may beincorporated in a network including a coexistence manager 570 and apolicy engine 574 that may be used to coordinate opportunistic use of LEbands with other secondary users/networks. The coexistence manager 670of a given network may include interfaces to the TVWS database 525 andcoexistence database 572, network devices and coexistence managers ofother networks. Location based LE band allocations may either bedistributed to base stations/HeNBs or centralized at the core network.The policy engine 574 may generate and enforce polices based on databaseinformation and operator defined rules.

A centralized hierarchical coexistence database management solutionmaybe used. A local database, for example coexistence database 572 inFIG. 5, which may be core network based, may be used to coordinatesecondary usage within a given operators network, while an Internetbased database may be used to coordinate secondary usage with externalusers/networks. Alternatively, a distributed approach may be implementedwhere there is no centralized entity to make spectrum allocationdecisions. In this approach, the eNB/HeNB may be responsible foraccessing the coexistence database, processing the spectrum sharingnegotiation with neighbor eNB/HeNBs, and making spectrum allocationdecisions.

A spectrum sensing coexistence solution may be implemented where thenetwork may rely on spectrum sensing results to coexist with othersecondary networks. For this approach, a new entity, for example sensingco-processor/enhanced sensing 550 in FIG. 5, at the eNB/HeNB maynegotiate access to LE bands by exchanging sensing and channel occupancyinformation with neighboring eNB/HeNBs. Alternatively, a centralizedapproach may be implemented based on spectrum sensing where a centralentity in the core network may process the spectrum sensing resultsreceived from eNBs/HeNBs and make decisions about eNB/HeNB channelassignments.

A contention based coexistence solution may be implemented by performingcarrier sensing for clear channel assessment (CCA) prior to commencingwith transmissions. The eNB may maintain control of grant and schedulingof transmission opportunities. However, transmissions may be “gated” bythe CCA.

Described herein is supplementary cell configuration and activation atan HeNB. Once the HeNB decides that it may activate a new supplementarycell, as the operating cells controlled by the IIeNB are experiencingcongestion, it first may seek the channel usage information from thecoexistence manager, which is triggered by a spectrum request. Thespectrum allocation of the HeNB may select the channel which triggerswithin the DSM RRM a series of events to correctly configure andactivate the new supplementary cell. Cell configuration at the HeNBrefers to determining all the cell parameters including defining theresources to be used as well as configuring the different LTE protocollayers for that specific cell in the HeNB. Cell activation at the HeNBrefers to starting the transmission and reception at the HeNB.

The configuration phase of the supplementary cell may determine the typeof channels it will operate in, (sublicensed, available or PU assigned),determine the requirement of coexistence gaps, configure the sensingtoolbox of the HeNB, select the amount of resources allocated to UL andDL, (i.e., TDD configuration no. 1-7 if an TDD frame structure;operating mode DL only, UL only or shared if an FDD frame structure). Inthe case of an TDD frame structure, a transmitting power level isdetermined, and RRM functions to consider the new SuppCC as a newresource, (packet scheduler, radio bearer control (RBC), and the like),may be configured. Transmission/reception in the supplementary cell maybe started. Although mandatory control information transmitted over thesupplementary cell may be reduced, some control information such as PSCHand SSCH may be still required to be broadcast. A cell activationprocedure for a set of connected WTRUs may be initiated.

Once the HeNB decides that is may release a supplementary cell, as theoperating cells controlled by the HeNB are experiencing less load, thesupplementary cell is experiencing an unacceptable level ofinterference, a primary user was detected in the case of a PU assignedchannel or it receives a request from the CM to evacuate the channel,this may trigger within the DSM RRM a series of events to correctlyrelease the new supplementary cell. RRM functions to consider that theresources associated with the released SuppCC are no longer available,(packet scheduler, RBC, and the like), may be configured. A deactivationcommand (e.g., MAC CE command), may be sent to all connected WTRUscurrently active on this supplementary cell. An RRC reconfiguration maybe sent to all current configured WTRUs on this supplementary cell torelease the supplementary cell. The CM may be informed that thesupplementary cell is released. New requirements may be determined formeasurement gaps. A sensing toolbox of the HeNB may be configured, andthe transmitting/receiving on the supplementary cell may be stopped.

EMBODIMENTS

1. A method of aggregating carriers, comprising providing an aggregatingcell configured for operation in a frequency division duplex (FDD)licensed spectrum.

2. The method of embodiment 1, further comprising aggregating theaggregating cell with at least one licensed exempt (LE) supplementarycell operating in a time sharing mode for uplink (UL) and downlink (DL)operations.

3. The method of any of the above embodiments, wherein the at least oneLE supplementary cell is an FDD supplementary cell dynamicallyconfigurable between an UL only mode, a DL only mode, and a shared modeto match requested UL and DL traffic ratios.

4. The method of any of the above embodiments, wherein for the sharedmode, the at least one LE supplementary cell is toggled between UL andDL at a toggling interval to match requested UL and DL traffic ratios.

5. The method of any of the above embodiments, wherein a sharing modepattern is based on sub-frame timing.

6. The method of any of the above embodiments, wherein a sharing modepattern repeats at a multiple of a number of hybrid automatic repeatrequest (HARQ) processes used by the aggregating cell.

7. The method of any of the above embodiments, wherein HARQ feedback istransmitted on one of the aggregating cell and the LE supplementarycell.

8. The method of any of the above embodiments, wherein HARQ feedback isbundled.

9. The method of any of the above embodiments, wherein a configurationchange is triggered by one of a radio resource control (RRC) message, amedium access control (MALC) control element (CE) command transmittedover the aggregating cell or a dedicated system information block (SIB)transmitted over the aggregating cell.

10. The method of any of the above embodiments, wherein multiple LEsupplementary cells are one of independently or dependently configured.

11. The method of any of the above embodiments, wherein the at least oneLE supplementary cell is a time division duplex (TDD) supplementarycell.

12. The method of any of the above embodiments, wherein the TDDsupplementary cell is dynamically configurable between multiple TDDconfigurations a given number of sub-frames after configuration changesignaling.

13. The method of any of the above embodiments, further comprisingproviding a guard period for UL/DL to DL/UL transitions that isdynamically configurable based on at least one of frequency, range, orsize of the TDD supplementary cell.

14. The method of any of the above embodiments, wherein timing forgrants and hybrid automatic repeat request (HARQ) feedback is based onthe aggregating cell FDD timing.

15. The method of any of the above embodiments, wherein the aggregatingcell transmits at least one of HARQ feedback, grants and channel stateinformation for the TDD supplementary cell.

16. The method of any of the above embodiments, further comprisingtriggering additional random access resources on the TDD supplementarycell on detecting a timing drift between the TDD supplementary cell andthe aggregating cell.

17. The method of any of the above embodiments, further comprisingproviding a coexistence capability for coordinating operations betweenthe LE supplementary cell with at least one of other networks and usersoperating in a same LE channel.

18. The method of any of the above embodiments, further comprisingproviding coexistence gaps to permit the other networks and usersoperating in the same LE channel as the LE supplementary cell to accessthe same LE channel.

19. A base station for licensed exempt spectrum aggregation, comprisinga dynamic spectrum management radio resource manager (RRM) configured toreceive cognitive sensing results from a sensing toolbox and toconfigure operation of the sensing toolbox.

20. The base station of embodiment 19, further comprising the RRMconfigured to control physical layer and a medium access layerconfigurations that provide coexistence gaps to permit other networksand users operating in a same licensed exempt (LE) channel as a LEsupplementary cell to access the same LE channel.

21. The base station of any of embodiments 19-20, further comprising theRRM configured to control a radio resource controller configuration todetect primary users and transition between different frequency divisionduplex (FDD) modes or time division duplex (TDD) uplink and downlinkconfigurations.

22. The base station of any of embodiments 19-21, further comprising acoexistence enabler interface configured to communicate between acoexistence manager and cognitive networks, wherein coexistence managerreconfiguration commands are translated into network-specificreconfiguration commands and transmitted to the cognitive network forreconfiguration, wherein the RRM receives translated coexistence managerreconfiguration commands from the coexistence enabler interface.

23. A wireless transmit/receive unit, comprising a radio resourcecontroller (RRC) and a medium access controller (MAC) configured toreceive configuration messages, the RRC and MAC being configured toprovide coexistence gaps to permit other networks and users operating ina same LE channel as a LE supplementary cell to access the same LEchannel, wherein a physical layer is configured by one of the RRC or MACaccording to the configuration message.

24. The WTRU of embodiment 23, further comprising the RRC beingconfigured to control a sensing toolbox to perform cognitive sensingmeasurements and support the coexistence gaps for primary/secondary userdetection.

25. The WTRUI of any of embodiments 23-24, further comprising the RRCbeing configured to detect primary users and transition betweendifferent frequency division duplex (FDD) modes or time division duplex(TDD) uplink and downlink configurations.

26. A management system, comprising a coexistence manager (CM) entityconfigured to manage inter-base stations as well as inter-operatorcoexistence operation.

27. The management system of embodiment 25, further comprising the CMconfigured to receive sensing and usage data, and licensed exempt (LE)spectrum information.

28. The management system of any of embodiments 26-27, furthercomprising the CM configured to process and forward the usage data torequesting base station.

29. The management system of any of embodiments 26-28, furthercomprising the CM configured to maintain a map of networks to identifyconflicts and coexistence operations based on at least the sensing andusage data, and LE spectrum information.

30. The management system of any of embodiments 26-29, furthercomprising the CM configured to transmit LE availability informationbased on at least the sensing and usage data, and the LE spectruminformation.

31. The management system of any of embodiments 26-30, wherein a rankingof available channels is sent to the base station.

32. A method comprising communicating via a primary carrier and asecondary carrier.

33. The method of any of embodiments 1-18 and 32, wherein the primarycarrier is in the FDD licensed spectrum and the secondary carrier is inthe licensed exempt spectrum.

34. The method of any of embodiments 1-18 and 32-33, further comprisingdynamically changing the supplementary carrier to aggregate in thedownlink or uplink.

35. The method of any of embodiments 1-18 and 32-34, further comprisingdynamically changing the direction of aggregation through a MAC CEcommand.

36. The method of any of embodiments 1-18 and 32-35, wherein the MAC CEcommand activates the supplementary carrier in one direction anddeactivates it in another.

37. The method of any of embodiments 1-18 and 32-36, further comprisingproviding a guard period (GP) for dynamic FDD priory to a frame boundarywhen switching the supplementary carrier from DL to UL or vice versa.

38. The method of any of embodiments 1-18 and 32-37, wherein the GP isconfigured based on the range or size of a cell.

39. The method of any of embodiments 1-18 and 32-38, wherein the GP isconfigured dynamically via RRC signaling.

40. The method of any of embodiments 1-18 and 32-39, further comprisingproviding a PHICH allocation sent over the RRC reconfiguration messagewhile configuring the supplementary carrier.

41. The method of any of embodiments 1-18 and 32-40, wherein the PHICHconfigurations are changed when the supplementary carrier isreconfigured.

42. The method of any of embodiments 1-18 and 32-41, wherein the PDCCHin the licensed band is modified based on PHICH allocations.

43. The method of any of embodiments 1-18 and 32-42, wherein on acondition that an unlicensed band carrier is set to DL only, theunlicensed band UL control information is sent over the primary carrier.

44. The method of any of embodiments 1-18 and 32-43, further comprisingdynamically changing the configuration of UL/DL in TDD using an RRCreconfiguration message.

45. The method of any of embodiments 1-18 and 32-44, further comprisingproviding a GP in the special sub frame for the TDD supplementarycarrier.

46. The method of any of embodiments 1-18 and 32-45, further comprisingdynamically adjusting to the range of the cell as well as the frequencyband of the unlicensed spectrum being used.

47. The method of any of embodiments 1-18 and 32-46, further comprisingproviding a preconfigured GP value per frequency band.

48. The method of any of embodiments 1-18 and 32-47, wherein periodicityand timing of a Sounding Reference Signal (SRS) are controlled by upperlayer parameters and are different between TDD and FDD.

49. The method of any of embodiments 1-18 and 32-48, further comprisingsending different subframe configurations for each carrier when both TDDand FDD configured.

50. The method of any of embodiments 1-1.8 and 32-49, further comprisingtransmitting the PUCCH only on the primary cell in an FDD fashion.

51. The method of any of embodiments 1-18 and 32-50, further comprisingtriggering additional PRACH on the supplementary carrier.

52. The method of any of embodiments 1-18 and 32-51, wherein an RRCconfiguration that is sent over the FDD carrier indicates the RACHconfiguration is specific to the TDD carrier.

53. The method of any of embodiments 1-1.8 and 32-52, wherein duringperformance of a PRACH on the secondary carrier (TDD), contentionresolution occurs on either the primary or supplementary carrier inorder.

54. The method of any of embodiments 1-18 and 32-53, further comprisingproviding a new entity in the eNB that is aware of the timing differencebetween the power control changes on the TDD and FDD carriers andapplying the appropriate TPC command.

55. The method of any of embodiments 1-18 and 32-54, further comprisingallowing cross-carrier scheduling of downlink resources on the TDI)supplementary carrier via the FDD carrier.

56. The method of any of embodiments 1-18 and 32-55, further comprisingsending bundled ACK/NACKs over the primary carrier.

57. The method of any of embodiments 1-18 and 32-56, further comprisingsending bundled ACK/NACK over the secondary carrier.

58. The method of any of embodiments 1-18 and 32-57, further comprisingsend the PHICH on the supplementary TDD carrier.

59. The method of any of embodiments 1-18 and 32-68, further comprisingallocating a new PDCCH search space in order to decode both TDD and FDDDCI formats which will be separate from the FDD PDCCH search space.

60. The method of any of embodiments 1-18 and 32-59, wherein UL grantsare signaled by the PDCCH using DCI format 0.

61. The method of any of embodiments 1-18 and 32-60, further comprisingproviding a new TDD DCI format 0 better aligned with the FDD DCI format.

62. The method of any of embodiments 1-18 and 32-61, further comprisingtreating to treat ACK/NACKs for supplementary TDD carrier as an FDDsupplementary carrier.

63. The method of any of embodiments 1-18 and 32-62, wherein upper layerevent reporting and measurements are modified given different timing forCQI reports coming from the TDD and FDD carrier.

64. The method of any of embodiments 1-18 and 32-63, further comprisingproviding a Coexistence Manager and Policy Engine to coordinateopportunistic use of Licensed Exempt bands with other secondaryusers/networks.

65. The method of any of embodiments 1-18 and 32-64, wherein theCoexistence Manager of a given network includes interfaces to theTVWS/Coexistence databases, network devices and Coexistence Managers ofother networks.

66. The method of any of embodiments 1-18 and 32-66, further comprisinga Policy Engine to generate and enforce polices based on database infoand operator defined rules.

67. The method of any of embodiments 1-18 and 32-66, wherein a newentity at the eNB/HeNB negotiates access to Licensed Exempt bands.

68. The method of any of embodiments 1-18 and 32-67, wherein carriersensing is performed for Clear Channel Assessment (CCA) prior tocommencing with transmissions.

69. A method of aggregating carriers comprising a frequency divisionduplex (FDD) primary cell aggregating a supplementary carrier.

70. The method of any of embodiments 1-18, 32-67 and 69, wherein thesupplementary carrier is a dynamic FDD supplementary carrier.

71. The method of any of embodiments 1-18, 32-67 and 69-70, wherein thesupplementary carrier is a licensed exempt carrier.

72. The method of any of embodiments 1-18, 32-67 and 69-71, wherein thesupplementary carrier is a time division duplex (TDD) supplementarycarrier.

73. The method of any of embodiments 1-18, 32-67 and 69-72, wherein theFDD primary cell includes uplink and downlink component carriers (CCs).

74. The method of any of embodiments 1-18, 32-67 and 69-73, wherein theCCs are activated or deactivated as needed.

75. The method of any of embodiments 1-18, 32-07 and 69-74, wherein oneof the CCs is deactivated between two time slots.

76. The method of any of embodiments 1-18, 32-67 and 69-76, wherein theCCs are in a downlink-only mode.

77. The method of any of embodiments 1-18, 32-67 and 69-76, wherein theCCs are in an uplink-only mode.

78. The method of any of embodiments 1-18, 32-67 and 69-77, wherein theCCs are in a shared mode.

79. A home evolved Node-B (HeNB) comprising a dynamic spectrummanagement (DSM) radio resource management (RRM) entity.

80. The HeNB of embodiment 79, further comprising a sensing toolboxconfigured to perform and process cognitive sensing on television whitespace (TVWS) and licensed exempt (LE) spectrum and reporting the resultsto the DSM RRM entity.

81. The HeNB of any of embodiments 79-80, further comprising a physical(PHY) layer.

82. The HeNB of any of embodiments 79-81, further comprising a mediumaccess control (MAC) layer.

83. The HeNB of any of embodiments 79-82, further comprising a radiolink control (RLC) layer.

84. The HeNB of any of embodiments 79-83, further comprising a packetdata convergence protocol (PDCP) layer.

85. The HeNB of any of embodiments 79-84, further comprising a radioresource control (RRC) layer.

86. A wireless transmit/receive unit (WTRU) comprising a dynamicspectrum management (DSM) radio resource management (RRM) entity.

87. The WTRU of embodiment 86, further comprising a sensing toolboxconfigured to perform and process cognitive sensing on television whitespace (TVWS) and licensed exempt (LE) spectrum and reporting the resultsto the DSM RRM entity.

88. The WTRU of any of embodiments 86-87, further comprising a physical(PHY) layer.

89. The WTRU of any of embodiments 86-88, further comprising a mediumaccess control (MAC) layer.

90. The WTRU of any of embodiments 86-89, further comprising a radiolink control (RLC) layer.

91. The WTRU of any of embodiments 86-90, further comprising a radioresource control (RRC) layer.

92. A home evolved management system (HeMS) comprising a coexistencemanager (CM) entity.

93. The HeMS of embodiment 91, further comprising an operator'scoexistence database

94. The HeMS of any of embodiments 91-93, further comprising a pluralityof policies, wherein the HeMS communicates with a television white space(TVWS) database via a coexistence discovery and information server(CDIS).

95. A method of aggregating carriers comprising aggregating licensedcarriers with at least one supplementary component carrier of a primarycell, wherein a guard period between uplink and downlink transitions arealtered based on a frequency of operation of the supplementary componentcarries.

96. An apparatus comprising a WTRU configured to perform any one of theabove-specified methods.

97. A computer readable medium having instructions stored thereon thatwhen executing by a WTRU cause the WTRU to perform any one of theabove-specified methods.

98. A wireless receive/transmit unit (WTRU) configured to perform themethod of any one of embodiments 1-18, 32-77 and 95.

99. The WTRU as in embodiment 98, further comprising a transceiver.

100. The WTRU as in any one of embodiments 98-99, further comprising aprocessor in communication with a transceiver.

101. The WTRU as in any one of embodiments 98-100, wherein a processoris configured to perform the method of any one of embodiments 1-18,32-77 and 96.

102. A network node configured to perform the method of any one ofembodiments 1-18, 32-77 and 95.

103. A Node-B configured to perform the method of any one of embodiments1-18, 32-77 and 95.

104. An integrated circuit configured to perform any one of embodiments1-18, 32-77 and 95.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element may be used alone or in combination with any of theother features and elements. In addition, the embodiments describedherein may be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals, (transmitted over wired or wireless connections), andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, a cache memory, a semiconductormemory device, a magnetic media, (e.g., an internal hard disc or aremovable disc), a magneto-optical media, and an optical media such as acompact disc (CD) or a digital versatile disc (DVD). A processor inassociation with software may be used to implement a radio frequencytransceiver for use in a WTRU, UE, terminal, base station, Node-B, eNB,HNB, HeNB, AP, RNC, wireless router or any host computer.

What is claimed is:
 1. A method of carrier aggregation, comprising:operating on a frequency division duplex (FDD) primary cell aggregatedwith a time division duplex (TDD) supplementary cell; receiving adownlink (DL) transmission in a sub-frame (n); determining a timing forhybrid automatic repeat request (HARQ) feedback for the DL transmission,wherein the HARQ feedback timing is set for a sub-frame (n+4); andsending the HARQ feedback on the FDD primary cell based on thedetermined timing.
 2. The method of claim 1, wherein the DL transmissionis on the TDD supplementary cell.
 3. The method of claim 1, wherein theDL transmission is on the FDD primary cell.
 4. The method of claim 1,wherein the FDD primary cell operates on a licensed spectrum.
 5. Themethod of claim 1, wherein the TDD supplementary cell operates on alicensed exempt (LE) spectrum.
 6. The method of claim 1, furthercomprising sending positive acknowledgement (ACK)/negativeacknowledgement (NACK) n+4 subframes following the DL transmission. 7.The method of claim 1, wherein the DL HARQ feedback is carried in aphysical UL control channel (PUCCH).
 8. The method of claim 7, whereinthe PUCCH is on the FDD primary cell.
 9. The method of claim 1, whereinmultiple TDD supplementary cells are aggregated, each TDD supplementarycell being one of independently or dependently configured.
 10. Awireless transmit/receive unit (WTRU), comprising: a processor; and amemory having stored instructions that when executed by the processorcause the WTRU to: operate on a FDD primary cell aggregated with a TDDsupplementary cell; receive a DL transmission in a sub-frame (n);determine a timing for HARQ feedback for the DL transmission, whereinthe HARQ feedback timing is set for a sub-frame (n+4); and send the HARQfeedback on the FDD primary cell based on the determined timing.
 11. TheWTRU of claim 10, wherein the DL transmission is on the TDDsupplementary cell.
 12. The WTRU of claim 10, wherein the DLtransmission is on the FDD primary cell.
 13. The WTRU of claim 10,wherein the FDD primary cell operates on a licensed spectrum and the TDDsupplementary cell operates on a LE spectrum.
 14. The WTRU of claim 10,wherein the WTRU sends an ACK/NACK n+4 subframes following the DLtransmission.
 15. The WTRU of claim 10, wherein the DL HARQ feedback iscarried in a PUCCH.
 16. The WTRU of claim 15, wherein the PUCCH is onthe FDD primary cell.
 17. A method of carrier aggregation, comprising:operating on a FDD primary cell aggregated with a TDD supplementarycell; sending an uplink (UL) transmission in a sub-frame (n);determining a timing for hybrid automatic repeat request (HARQ) feedbackfor the UL transmission, wherein the HARQ feedback timing is set for asub-frame (n+4); receiving the HARQ feedback on the FDD primary cell;and associating the HARQ feedback with the UL transmission based on thedetermined timing.
 18. The method of claim 17, wherein the ULtransmission is on the TDD supplementary cell.
 19. The method of claim17, wherein the UL transmission is on the FDD primary cell.
 20. Themethod of claim 17, wherein the FDD primary cell operates on a licensedspectrum.
 21. The method of claim 17, wherein the TDD supplementary celloperates on a licensed exempt (LE) spectrum.
 22. The method of claim 17,further comprising receiving an ACK/NACK n+4 subframes following the ULtransmission.
 23. The method of claim 17, wherein UL HARQ feedback iscarried in a modified physical HARQ indicator channel (PHICH).
 24. Themethod of claim 23, wherein the PHICH is carried on the primary cell.25. The method of claim 17, wherein multiple TDD supplementary cells areaggregated, each TDD supplementary cell being one of independently ordependently configured.
 26. The method of claim 17, wherein the primarycell or the TDD supplementary cell carries UL grant information.